Ultrasonic robotic surgical navigation

Abstract

Surgical robot systems, anatomical structure tracker apparatuses, and US transducer apparatuses are disclosed. A surgical robot system includes a robot, a US transducer, and at least one processor. The robot includes a robot base, a robot arm coupled to the robot base, and an end-effector coupled to the robot arm. The end-effector is configured to guide movement of a surgical instrument. The US transducer is coupled to the end-effector and operative to output US imaging data of anatomical structure proximately located to the end-effector. The least one processor is operative to obtain an image volume for the patient and to track pose of the end-effector relative to anatomical structure captured in the image volume based on the US imaging data.

What is claimed is: 
     
       1. A method by a surgical robot system of a robot having a robot base, a robot arm coupled to the robot base, and an end-effector coupled to the robot arm, the end-effector configured to guide movement of a surgical instrument, the method comprising:
 receiving ultrasound (US) imaging data from an ultrasound (US) transducer coupled to the end-effector, wherein the US imaging data is of anatomical structure proximately located to the end-effector; 
 obtaining an image volume for the patient; and 
 tracking pose of the end-effector relative to anatomical structure captured in the image volume based on the US imaging data. 
 
     
     
       2. The method of  claim 1 , wherein tracking of pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data, comprises:
 generating US images of the anatomical structure based on the US imaging data; 
 matching the anatomical structure captured in one of the US images to the anatomical structure captured in the image volume; and 
 determining the pose of the end-effector relative to the anatomical structure captured in the image volume based on the matching. 
 
     
     
       3. The method of  claim 1 , wherein the end-effector comprises a guide tube configured to guide movement of the surgical instrument through the guide tube, the US transducer comprises an array of US transducers spaced apart along a leading edge of the guide tube, and the receiving of the US imaging data comprises receiving the US imaging data from the array of US transducers. 
     
     
       4. The method of  claim 3 , wherein the US transducers are spaced apart to form a ring shape and are at least partially disposed within the leading edge of the guide tube, and the tracking pose of the end-effector relative to the anatomical structure captured in the image volume comprises determining pose of the end-effector relative to the leading edge of the guide tube. 
     
     
       5. The method of  claim 1 , wherein the US transducer comprises a planar array of US transducers connected by a mounting arm to the end-effector, and the receiving of the US imaging data comprises receiving the US imaging data from the planar array of US transducers. 
     
     
       6. The method of  claim 1 , further comprising:
 identifying in the US imaging data locations of discrete features which are spaced apart along the surgical instrument and sensed by the US transducer; and 
 determining pose of the surgical instrument relative to the end-effector based on the locations of the discrete features identified in the US imaging data. 
 
     
     
       7. The method of  claim 6 , wherein the surgical instrument has a shaft with the discrete features configured as indentations, protrusions, slots, and/or holes spaced apart along a surface of the surgical instrument, and the determining of the pose of the surgical instrument comprises identifying location of the indentations, protrusions, slots, and/or holes. 
     
     
       8. The method of  claim 6 , wherein:
 the US transducer comprises an array of US transducers; and 
 the determining of the pose of the surgical instrument relative to the end-effector based on the locations of the discrete features identified in the US imaging data, comprises:
 determining depth of the surgical instrument relative to a location on the end-effector based on counting a number of the discrete features identified in the US imaging data from individual ones of the US transducers; and 
 determining rotation of the surgical instrument relative to the end-effector based on identifying rotation of the discrete features identified in the US imaging data between adjacent US transducers in the array. 
 
 
     
     
       9. The method of  claim 6 , wherein the determining of the pose of the surgical instrument relative to the end-effector based on the locations of the discrete features identified in the US imaging data, comprises:
 matching a spatial pattern of the locations of the discrete features identified in the US imaging data to content of a template for the surgical instrument which defines a pattern of the discrete features arranged around the surface of the surgical instrument as a function of locations along a length of the surgical instrument. 
 
     
     
       10. The method of  claim 1 , further comprising:
 identifying in the US imaging data locations of layers of materials of the surgical instrument, wherein adjacent layers of the materials have different reflectivity to ultrasound; and 
 determining pose of the surgical instrument relative to the end-effector based on the locations of the layers of materials of the surgical instrument identified in the US imaging data. 
 
     
     
       11. The method of  claim 10 , wherein the surgical instrument has a shaft with layers of materials stacked along a primary axis of the shaft, wherein adjacent layers of the materials have different reflectivity to US, and the determining of the pose of the surgical instrument relative to the end-effector comprises identifying the locations of the stacked adjacent layers of the materials. 
     
     
       12. The method of  claim 10 , further comprising the surgical instrument having a shaft with layers of materials forming helical stripes spiraling about a primary axis of the shaft, wherein adjacent layers of the materials have different reflectivity to US, and the determining of the pose of the surgical instrument relative to the end-effector comprises identifying the locations of the helical striped adjacent layers of the materials. 
     
     
       13. The method of  claim 10 , further comprising the surgical instrument having a shaft with layers of materials forming stripes extending parallel to a primary axis of the shaft, wherein adjacent layers of the materials have different reflectivity to US. 
     
     
       14. The method of  claim 1 , further comprising:
 determining a target pose for the surgical instrument based on a surgical plan defining where a surgical procedure is to be performed using the surgical instrument on the anatomical structure captured in the image volume; and 
 generating steering information based on the target pose for the surgical instrument and a present tracked pose of the end-effector relative to the anatomical structure captured in the image volume, the steering information indicating where the surgical instrument and/or the end-effector need to be moved. 
 
     
     
       15. The method of  claim 14 , wherein the surgical robot system has at least one motor operatively connected to move the robot arm relative to the robot base, and the method further comprises:
 controlling movement of the at least one motor based on the steering information to guide movement of the end-effector so the surgical instrument becomes positioned with the target pose. 
 
     
     
       16. The method of  claim 1 , wherein the surgical robot system has kinematic sensors connected to the robot arm and operative to output kinematic movement data indicating change in pose of the robot arm relative to the robot base, and the method further comprises:
 after tracking pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data for a period of time and responsive to determining the US transducer has ceased to output US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on the kinematic movement data; and 
 responsive to determining the US transducer has resumed output of US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data. 
 
     
     
       17. The method of  claim 16 , wherein the triggering of continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data, comprises:
 generating US images of the anatomical structure based on the US imaging data; 
 selecting a portion of the image volume based on a present pose of the end-effector as tracked relative to the anatomical structure captured in the image volume based on the kinematic movement data; 
 matching structure of the anatomical structure captured in one of the US images to structure of the anatomical structure captured in the selected portion of the image volume; and 
 determining the pose of the end-effector relative to the anatomical structure captured in the selected portion of the image volume based on the matching. 
 
     
     
       18. The method of  claim 16 , further comprising:
 displaying a graphical representation of the end-effector with the determined pose relative to a graphical representation of the anatomy captured in the image volume; and 
 using a different color and/or shading to display the graphical representation of the end-effector relative to the graphical representation of the anatomy captured in the image volume to visually indicate to a user when the pose of the end-effector relative to the anatomical structure captured in the image volume is being tracked based on the US imaging data distinguishable by the user from when the pose of the end-effector relative to the anatomical structure captured in the image volume is being tracked based on the kinematic movement data. 
 
     
     
       19. The method of  claim 1 , wherein the surgical robot system has a tracking camera operative to track pose of markers on the robot arm and/or the end-effector, and the method further comprising:
 after tracking pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data for a period of time and responsive to determining the US transducer has ceased to output US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on output of the tracking camera; and 
 responsive to determining the US transducer has resumed output of US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data. 
 
     
     
       20. The method of  claim 1 , wherein the surgical robot system has a tracking camera operative to capture location of markers on the robot arm and/or the end-effector, and the method further comprising:
 tracking pose of the markers; 
 after tracking pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data for a period of time and responsive to determining the US transducer has ceased to output US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on output of the tracking camera; and 
 responsive to the determining the US transducer has resumed output of US imaging data of the anatomical structure proximately located to the end-effector, triggering continued tracking of the pose of the end-effector relative to the anatomical structure captured in the image volume based on the US imaging data.